RESEARCH ARTICLE

The Vjosa River corridor: a model of natural hydro-morphodynamics and a hotspot of highly threatenedecosystems of European significance

Fritz Schiemer . Sajmir Beqiraj . Anton Drescher . Wolfram Graf .

Gregory Egger . Franz Essl . Thomas Frank . Christoph Hauer .

Severin Hohensinner . Aleko Miho . Paul Meulenbroek . Wolfgang Paill .

Ulrich Schwarz . Simon Vitecek

Received: 22 October 2019 /Accepted: 6 March 2020 / Published online: 20 March 2020

� The Author(s) 2020

Abstract

Context Large near-natural rivers have become rare

in Europe, a fact reflected in the high conservation

status of many riverine ecosystems. While the Balkan

still harbors several intact river corridors, most of

these are under pressure from planned hydropower

constructions. Unfortunately, there is little informa-

tion available on the hydromorphodynamics and biota

of Balkan rivers under threat.

Objectives We present a synthesis of research on the

Vjosa in Southern Albania. Here, longitudinal conti-

nuity in water flow, undisturbed sediment transport

and intact fluvial dynamics are still maintained, but

threatened by two large dams planned in its down-

stream section. We intend to provide a first multidis-

ciplinary inventory of this river system as an example

of the knowledge base required for sound water

management decisions in the Balkans.

Methods Based on field work of a multidisciplinary

consortium of scientists from Albania and other

countries conducted from 2017 onwards, we summa-

rize the most important findings on geomorphology ofElectronic supplementary material The online version ofthis article (https://doi.org/10.1007/s10980-020-00993-y) con-tains supplementary material, which is available to authorizedusers.

F. Schiemer (&)

Department of Limnology and Bio-Oceanography,

University of Vienna, Althanstr.14, Vienna 1090, Austria

e-mail: friedrich.schiemer@univie.ac.at

S. Beqiraj � A. Miho

Department of Biology, University of Tirana, Tirana,

Albania

e-mail: sajmir.beqiraj@fshn.edu.al

A. Miho

e-mail: aleko.miho@fshn.edu.al

A. Drescher

Instiutute of Biology, Division of Plant Sciences,

University of Graz, Holteigasse 6, Graz 8010, Austria

e-mail: anton.drescher@uni-graz.at

W. Graf � S. Hohensinner � P. Meulenbroek

Institute of Hydrobiology and Aquatic Ecosystem

Management, University of Natural Resources and Life

Sciences, Gregor-Mendel-Straße 33, Vienna 1180, Austria

e-mail: wolfram.graf@boku.ac.at

S. Hohensinner

e-mail: severin.hohensinner@boku.ac.at

P. Meulenbroek

e-mail: paul.meulenbroek@boku.ac.at

G. Egger

Institute of Geography and Geoecology, Department of

Wetland Ecology, Karlsruhe Institute of Technology,

Josefsstraße 1, Rastatt 76437, Germany

e-mail: gregory.egger@kit.edu

123

Landscape Ecol (2020) 35:953–968

https://doi.org/10.1007/s10980-020-00993-y(0123456789().,-volV)( 0123456789().,-volV)

the riverine landscape, habitat turnover rates, vegeta-

tion ecology and selected animal taxa.

Results We found evidence that significant areas

(86%) of the river corridor are covered by habitats

listed in Annex 1 of the European Union Habitats

Directive. These are associated with a high number of

threatened biota.

Conclusions Our findings underscore the value of

the Vjosa as one of the few remaining reference sites

for dynamic floodplains in Europe and as a natural

laboratory for interdisciplinary research. We empha-

size that such multidisciplinary studies are a prereq-

uisite for informed evaluation of potential impacts

caused by hydropower plants.

Keywords Balkans rivers � EU-regulations � Habitatturnover � Hydropower � Stenotopic floodplain biota �Vegetation succession

The Balkans—the blue heart of Europe

Stretching from Slovenia to northern Greece, the

Balkans (Balkan Peninsula, see Fig. 1) are home to

most of the remaining intact river systems in Europe

with the exception of the arctic and boreal ecoregions.

The majority of Balkan rivers are in an excellent

hydromorphological state, a situation that is highly

exceptional in Europe. This holds especially true for

Montenegro and Albania (Fig. 1). The region in

general, and its rivers in particular, are recognized as

biodiversity hotspots with many endemic species

(Griffith et al. 2004). However, recently, Balkan rivers

have come under strong pressure from around 3000

planned hydropower projects, of which more than

1000 are located in protected areas such as national

parks, nature reserves and Natura 2000 sites (see

‘‘Eco-Masterplan for Balkan rivers’’ 2018). In many

cases, the conservation value of rivers impacted by the

proposed hydropower projects is insufficiently known,

and environmental impact assessments are often

inadequate.

Here, we provide a multidisciplinary synthesis of

the conservation value of the Vjosa in southern

Albania which is one of the last large European rivers

in excellent hydromorphological condition throughout

its entire course. The river has recently come under

threat from two commissioned hydropower dams at its

lower section (see Fig. 2a). While it is evident that the

construction of these hydropower plants would have a

severe impact on the conservation value of the Vjosa,

the decision for constructing these dams has been

made without a comprehensive assessment of possible

environmental and socio-economic effects and with-

out considering possible alternatives.

Thus, a joint action of research teams from Albania,

Austria and Germany was instigated in 2017 to survey

the river sections that would be directly affected.

While the detailed results have been made available in

a recent monograph (Schiemer et al. 2018a, b), here

we provide a synthesis of the results and discuss them

in a broader context. In particular, we address the

geomorphological dynamics of the river and its

floodplains, examine habitat diversity and habitat

turnover rates, present a model on vegetation succes-

sion and discuss characteristic aquatic and terrestrial

F. Essl

Department of Botany and Biodiversity Research,

University of Vienna, Rennweg 14, Vienna 1030, Austria

e-mail: franz.essl@univie.ac.at

T. Frank

Institute of Zoology, University of Natural Resources and

Life Sciences, Gregor-Mendel-Straße 33, Vienna 1180,

Austria

e-mail: thomas.frank@boku.ac.at

C. Hauer

Christian Doppler Laboratory for Sediment Research and

Management, University of Natural Resources and Life

Sciences, Muthgasse 107, Vienna 1190, Austria

e-mail: christoph.hauer@boku.ac.at

W. Paill

Universalmuseum Joanneum, Weinzottlstraße 16,

Graz 8045, Austria

e-mail: wolfgang.paill@museum-joanneum.at

U. Schwarz

Fluvius: Floodplain Ecology and River Basin

Management, Hetzgasse 22, Vienna 1030, Austria

e-mail: office@fluvius.com

S. Vitecek

WasserCluster Lunz, Dr.-Carl-Kupelwieser Promenade 5,

Lunz 3293, Austria

e-mail: simon.vitecek@wcl.ac.at

123

954 Landscape Ecol (2020) 35:953–968

fauna. Our results support the urgency for

conservation.

Study site and methods

A detailed description of the Vjosa and its accompa-

nying landscapes is available in Schiemer et al.

(2018a, b). In brief, the river extends over 272 km

from its sources in the Pindos mountains (at

1343 m.a.s.l.) east of Ioannina in Greece through the

south of Albania to the Adriatic Sea. Its catchment

covers 6704 km2 of which 4365 km2 are on Albanian

territory. The first 80 km are situated in Greece, where

the river is named Aoos. The overall geomorphology

of the Vjosa basin is characterized by a NW–SE

orientation of the folded structures and tectonic planes

(Fig. 2a). Along its course a variety of channel types

occurs, with gorges in the upper parts, braiding and

anabranching sections in the middle and lower courses

and meandering stretches close to the river mouth. The

climate of the lower catchment is Mediterranean,

grading further upstream into sub-Mediterranean,

temperate and finally—at its source in the moun-

tains—alpine climates. The hydrological regime is

classified as pluvio-nival. On average, the flow of the

river exhibits a distinct seasonal pattern with high

discharge from December to April, intermediate flows

Fig. 1 Hydromorphological status of rivers with a catchment

size over 500 km2 in the Balkan Peninsula (acc. to ‘‘Ecomas-

terplan Balkan 2018). Class 1 near-natural, class 2 slightly

modified, class 3 moderately to severely modified. Balkan

countries SL (Slovenia), HR (Croatia), RS (Serbia), BA

(Bosnia-Herzegovina), ME (Montenegro), AL (Albania), KV

(Kosovo), GR (Greece), BG (Bulgaria), TR (Turkey). Neigh-

boring countries AT (Austria), HU (Hungary), RO (Romania),

IT (Italy). Within the Balkan 25% of the rivers are hydromor-

phologically in ‘‘near to natural’’ conditions (compared to 10%

in Germany)

123

Landscape Ecol (2020) 35:953–968 955

in May and October and low flow from June to

September. Daily discharge is highly unpre-

dictable (Fig. 2b). The annual mean flow at Pocemi

is 141.5 m3s-1, the recorded maximum was 3140

m3s-1 (1963).

Our assessment focused on the lower section of the

Vjosa at Pocemi and Kalivaci, which represents a bar-

braided and island braided river type with extensive

floodplains (Fig. 3a). We identified the hydro-mor-

phological and habitat dynamics of the river-flood-

plain system at a range of spatio-temporal scales. The

landscape development over the past 50 years was

reconstructed from a series of satellite images from

1968 onwards. In a detailed review of about 30

available images, those from 1968, 2006, 2012 and

2016 (Google Earth 2018) were analyzed with regard

to the long-term translocations of the active channel

within the floodplain. Satellite images were selected

according to their temporal distribution, water level

and spatial resolution for interpretation.

To gain a better understanding of the driving forces

of the landscape dynamics, terrestrial surveys along

three representative transects of the river-floodplain

morphology were conducted using a Leica TC805

Fig. 2 a The Vjosa catchment. Shown are major mountain

ranges in Albania (dotted line) and the major cities: Mif

(Mifoli), Sel (Selenica), Poc (Pocemi), Kal (Kalivaci), Tep

(Tepelena), Per (Permet), Car (Carshova), Gji (Gjirokastro). The

study area upstream of Pocemi, where the two hydropower

plants are planned, is indicated by a circle. bDaily discharges of

the Vjosa for the time period 1958–1990. Hydrometer at Dorez,

(upstream of Pocemi). After 1990 the gauging station was

closed. The broken horizontal lines at 300 m3s-1 and 1,000

m3s-1 indicate the initiation of bed load transport in the channel

and the discharge overtopping into the floodplains, respectively

123

956 Landscape Ecol (2020) 35:953–968

total station in April 2017 and July 2018 (Figs. 3a, 4).

Integrating this analysis of relief changes of the

riverine landscape with available flow data allows for

an approximation of the extensive sediment transport

and morpho-structural dynamics. Morphological clas-

sification (following Nanson and Knighton 1996) of

the floodplain at Pocemi was achieved with a one-

dimensional hydrodynamic-numerical model: bank-

full discharge capacity (m3s-1), bottom shear stress

(Nm-2) and unit stream power (Wm-2) were analyzed

for characteristic discharges (mean flow – maximum

recorded floods). For measurements of sediment

transport processes see Hauer et al. (2019).

For an assessment of habitat distribution and

turnover at smaller scale satellite images were ana-

lyzed from 2006, 2012 to 2016 (Fig. 5, Table 2).

Vegetation surveys were carried out in 69 plots

(releves) along the three transects in April and

September 2017 and compared to the analysis of

satellite images. Plot size varied between 25 and 100

m2, depending on vegetation type. Obtained data were

classified using TWINSPAN (Hill 1979) to describe

succession patterns of floodplain vegetation (Fig. 6b).

For details see Drescher 2018.

Habitats covered by the EU Habitats Directive

(Annex 1, European Commission 2013) of the river

corridor of the Pocemi—Kalivaci section were

Fig. 3 a Satellite overviews (2012) of the river-floodplain

section upstream of Pocemi. The ‘‘active channel’’ (AC) is

represented by the bright band. Delineated are the outer borders

of the ‘‘active floodplain’’ (AF) and the ‘‘morphological

floodplain’’ (MF), defined by the breadth of the valley floor.

The AF is regularly (at a high flow of approximately 5–10 years

flood recurrence) flooded. The MF, the area outside the AF, is

only flooded sporadically at very high floods (high flow[ 100

years). This area is largely used as arable land. The solid

rectangular box delineates the area where three transects were

established to study habitat, morphological and biotic compo-

sition and turnover during the study period. b Long-term

translocation of the active channel between 1968 and 2016. The

outer borders of the morphological floodplains are marked

123

Landscape Ecol (2020) 35:953–968 957

mapped in May 2019 in combination with aerial

images (Esri) (Egger et al. 2019).

The study of the diversity of benthic invertebrate

fauna was designed as a faunistic survey, conducted as

a stratified sampling program along three transects.

Larval samples were taken with a 250 lm25 9 25 cm hand net, observing standardized sam-

pling routines. Additionally, adult aquatic insects were

collected with sweep nets and light trapping.

Juvenile and adult fish were caught by point

abundance electrofishing (EF) (Copp and Penaz

1988) at wadable sites in April 2017. For EF, a

backpack-generator (ELT60-IIH from H. Grassl) was

used. Additional gill nets were placed at selected sites

with a mesh size of 20 mm and 50 mm. For more

detailed information see Meulenbroek et al. (2018).

Surveys on the riparian invertebrate fauna were

conducted from 24.04.2017 to 28.04.2017. In

particular, 150 pitfall traps were applied at 30 sites

arranged along Transect 2 (Fig. 3a) with 20 additional

sampling sites studied by time-standardized hand-

collections. To record amphibian and reptile species,

transect campaigns along the Vjosa River were

performed in 2016 and 2017.

Results

Landscape dynamics

There is a clear distinction between the active channel

(bright band) and the elevated floodplain (Fig. 3a).

The width of the active channel (AC) varies between

400 and 1000 m. Larger islands and gravel bars within

the AC are strongly structured by erosion channels and

show the cumulative effects of changing water levels

Fig. 4 Change in the river-floodplain relief from 2017 to 2018 along three transects shown in Fig. 3a. Distances along the transect from

left (as anchor point) to right. The horizontal line marks the water level at the flow during sampling in 2017 (approx. 50 m3s-1)

123

958 Landscape Ecol (2020) 35:953–968

and flow pulses. Within the AC large bars are

deposited and more perennial islands are formed as

is characteristic for island braided river sections. The

river segments under consideration are partially con-

strained by bedrock structures leading to a high

variability in the lateral extent of the riverine land-

scape. Gorges constitute bottlenecks in sediment

transport resulting not only in lateral but also in

longitudinal sorting processes. Besides the high gravel

load, a large amount of finer sediments is transported

by the river – a significant feature that creates large silt

deposit areas but also causes high compaction and

reduced porosity of the river bed. The floodplain is

characterized by extraordinarily high dynamics and

relocation of the AC, partially due to channel avulsion

(Fig. 3b). Its average relocation rate for the period

between 1968–2016 was in the order of 1–1.4% per

year of the AC area, which means that the river-

floodplain system is completely restructured within

less than 100 years.

The impact of the flow dynamics is apparent from

the two series of cross-sectional measurements over

Fig. 5 Mid-term structural changes in the river – floodplain

area of the Pocemi floodplain between 2012 and 2016. The

graph shows the almost complete change in position of the

anabranching river system. The dark area shows the overlap in

the position of the river between 2012 and 2016

123

Landscape Ecol (2020) 35:953–968 959

the river-floodplain system in April 2017 and 2018. In

between the two series a major flood event occurred in

December 2017 (estimated discharge: 2000 m3s-1,

HQ5: 5 years flood recurrence time). The effects can

be seen in both in the vertical as well as the lateral

changes of the river bathymetry andmajor side erosion

in curved sections (see arrows in Fig. 4). Vertical

aggregation and scouring occur in all parts of the main

AC. The scarp at the border of the AC and the elevated

floodplain is on average 2–3 m high, measured from

Fig. 6 a A general scheme of habitat composition and habitat

turnover cycles (encircled). The percentage fraction of the

various habitat types (aquatic: dark grey, upwards directed;

terrestrial: bright grey, downwards directed columns) refer to

the study area at Pocemi delineated in Fig. 3a during the period

2012–2016. The columns are arranged along the x-axis with

respect to their theoretical turnover rate. b Vegetation succes-

sion model: The heading denominates the progressive

succession from the initial stages B0 and C0 to woodland

(BC4). The dashed lines with arrows indicate a continued

development. The succession is frequently interrupted and reset

by flood events, depending on the distance from the main

channel and elevation. The B- and C-series represent the

difference in the succession series starting on coarse and fine

grained sediment respectively. Dominant species are printed in

bold. For a detailed discussion see text

123

960 Landscape Ecol (2020) 35:953–968

the mean water level of the main river arm. The

analysis of the discharge capacity of the AC indicates

an overtopping of flow into the overbank areas at

around 1000 m3s-1 (Fig. 1b), which represents the

height of an approximately annual flood event in the

investigated river sections. The modelling approach

enabled a quantification of driving morpho-dynamic

parameters like bottom shear stress or stream power

(22.8 W m-2 – 39.8 W m-2) for 1000 m3s-1 dis-

charge. These numbers are at the lower boundary of

gravel-dominated laterally active rivers (Nanson and

Knighton 1996), such rivers being transitional

between meandering and braided types (Deslodges

and Church 1989). In the study site, extended stretches

can be classified as island-braided with tendencies to

anabranching. Channel sinuosity as well as the ratio of

island length/channel width supported the classifica-

tion of a laterally active gravel-bed river.

Based on direct sediment transport measurements

in 2018, the initiation of bed load transport starts at

300–350 m3s-1. Flows at or above these critical values

occurred on average at 29 ± 21 days per year from

1958–1990 (Fig. 1b). Total load of transported sedi-

ments based on flow data for 2018, and on direct

sediment transport monitoring techniques both of bed

load and suspended sediments, yielded values of 5

Mil. tons a-1 for the Pocemi section, which constitutes

a significant contribution to delta development and

coastal protection (Hauer et al. 2019). The portion of

suspended sediment is high: an interesting finding of

the transect measurements (Fig. 4) is that the water

levels of the main arm, the disconnected arms and

erosion pools differ by up to one meter. This confirms

that the lateral groundwater exchange is low, due to

the high clogging of the riverine sediments.

Dynamic rivers create a wide range of habitat types

and transition zones which change continuously at

different spatio-temporal scales (see Table 1). Within

the AC, aquatic habitats range from fast current to

stagnant conditions. Their ecological characteristics—

at a microhabitat scale—vary continuously with water

table height. Even small water level fluctuations and

‘‘flow pulses’’ lead to continuous changes in the

flowage line and habitat conditions, especially for the

aquatic biota and the riparian fauna.

Terrestrial habitat types on elevated bars within the

active channel and the elevated floodplains exhibit an

even higher complexity. The main factors for differ-

entiation are: (a) sediment sorting processes and

sediment composition (grain size diameter) as a main

factor for water capacity of the sediments and thus the

germination of plants, (b) distance from the main river

branches, (c) elevation above mean water table,

(d) frequency and dimension of flow pulses resulting

in different time spans for vegetation development,

(e) the groundwater table, (f) timing and mode of seed

dispersal, and (g) human impacts by logging, burning,

or grazing. Within the active channel we can identify

successions on gravel (B series) and on sand/ silt

deposits (C series) with higher water retention. On

higher islands within the AC and in the elevated

floodplain areas, the continuous dynamics of sedi-

mentation and erosion processes lead generally to

vertically structured depositions with alternating lay-

ers of coarser and finer sediments. As a consequence of

several years of sedimentation a clear floristic distinc-

tion between a gravel (B-) and a fine sediment (C-)

series is no longer possible (therefore BC3 and BC4 in

Table 1, see Fig. 6b).

For the analysis of the quantitative composition of

habitat elements and their spatio-temporal dynamics

(Table 2), some of the habitat types were combined

because they were either continuously interchanging

with water level fluctuations (e.g. the riverine habitats

A1–A4) or were not clearly discernable in the satellite

images. The river with its downstream connected or

disconnected side-arms (A1–A4) represents approxi-

mately 15–20% of the AC at low and mean water

levels. The areal extent of erosion pools (type A5) is

very low, yet they are very significant as habitat and

refuge for many riverine landscape species. The

unvegetated gravel and sand bars (B0 and C0) cover

the largest area, about 50% of the AC. Small patches of

softwood floodplain forests (BC4) can be found on

larger accreted islands. Within the elevated floodplain

such softwood floodplain forest patches are also rare

and cover only small areas. The same holds true for

wetlands (A6 and A7). At the elevated floodplains

where grassland is dominant (D), turnover is expect-

edly lower and the observed structural changes are

mainly due to human activities by grazing and

burning.

The habitat turnover rates are particularly high

within the AC (see Table 2, Fig. 5). The position of the

multichannel river and all the major habitat elements,

including smaller islands pioneer vegetation and

shrubs, changes in the order of 10–20% per year at

the habitat scale. Isolated erosion pools within the

123

Landscape Ecol (2020) 35:953–968 961

active channel are specifically short-lived due to

erosion and sedimentation, with a life-cycle of less

than one year.

Our data highlight two significant features of

habitat dynamics (see also Fig. 6a): firstly, the

proportion of habitat elements remains constant over

time, but—secondly—the continuous shift in the

location of the various habitat types indicates a fast

turnover and renewal cycle: the whole river-floodplain

Table 1 Habitat types in the river floodplain of the Vjosa river, at low to mean flow, maintained by periodic flood conditions

Aquatic habitat types

A1: Main branches of the river, fast current in the thalweg

A2: Inshore zone of the main branch and shallow side branches, low current

A3: Downstream connected side-branches, partially with percolating flow

A4: Disconnected side-branches

A5: Erosion pools within the active channel

A6: Backwaters and riparian wetlands at lower levels within the floodplains

A7: Wetlands along hillslope streams entering the floodplains

Terrestrial habitats within the AC on coarse grained sediments

B0: Initial habitats on coarse-grained sediment bars without vegetation or with sparse seedlings,\ 0.5 years old,\ 5% cover

B1: Pioneer habitats on coarse-grained sediment bars with seedlings of annual and perennial herbs (dominant) and woody

species ([�–1.5 years old,1–30 cm high,\ 15% cover)

B2: Shrub on coarse-grained sediment bars with dominant woody species ([ 1.5–3 years old, 50–200 cm high)

Terrestrial habitats within the AC on fine grained sediments

C0: Initial habitats on fine-grained sediment, bars without vegetation or with sparse seedlings, 0.5 years old,\ 5% cover

C1: Pioneer habitats on fine-grained sediment bars with seedlings of annual and perennial herbs and woody species

(0,5–1.5 years old, 1–30 cm high,\ 15% cover)

C2: Shrub on fine-grained sediment, bars and islands (annual and perennial herbs and woody species ([ 1.5–3 years, 50–200 cm

high)

At elevated islands within the AC and on the floodplains

BC3: Closed shrub on sediment bars and islands with dominating woody species and perennial herbs ([ 3–8 years

old, = [ 200 cm high)

BC4: Woodland with beginning humus accumulation on higher islands and elevated floodplain levels ([ 8–30 years, till 10 m

tall)

Degradation types

D: Heavily grazed and/or regularily burned Imperata-grasslands with a variety of shrub species, e.g. Tamarix parviflora, Vitex

agnus-castus and Platanus orientalis

Table 2 Habitat composition in the Vjosa floodplain (see Table 1; in % of the AC area) and habitat turnover rates (in % per year)

within the AC

2006–2012 2012–2016

% Area % Turnover % Area % Turnover

River branches (A1–A4) 16,7 13,4 19,4 19,2

Erosion pools (A5) 0,4 100 0,6 23,0

Initial and pioneer phase (B0, B1, C0, C1) 43,7 8,7 51,6 9,7

Shrub phase (B2, C2) 26,4 11,4 18,2 17,8

Advanced shrub phase (BC3) 12,8 13,7 10,2 14,8

The values refer to the study area delineated in Fig. 2. The average area of the AC and of the active floodplain (AF) are 560 ha each

123

962 Landscape Ecol (2020) 35:953–968

system is in a state of a dynamic hydro-morphological

equilibrium. Accordingly, we found that:

(a) Microhabitat availability is continuously shift-

ing with water level fluctuations and small scale

sediment transport processes above a flow of

300–350 m3s-1.

(b) The average renewal rate of aquatic and riparian

habitats in the AC occurs at a time scale of

approx. every 5–10 years due to the cumulative

effect of regular, annual floods (HQ 1) (see

Table 2 and Fig. 5).

(c) Restructuring of the complete floodplain occurs

in an order of 50–100 years as a compound

result of major flood events.

We suggest that this pattern found for the Vjosa is

characteristic for large, undisturbed Balkan gravel bed

rivers.

The generalized model of vegetation succession in

context with habitat turnover (Fig. 6b) shows that

succession on gravel deposits starts with herbs and

grasses (Chondrilla juncea, Dittrichia graveolens,

Cynodon dactylon, Tragus racemosus—B0), followed

by seedlings of Tamarix parviflora, Salix spp. (S.

amplexicaulis, S. eleagnos, S. alba) and Populus nigra

(B1) which develop into a low shrub (B2). The initial

stage of succession on silt and sand (C-series) is

dominated by Agrostis stolonifera and Xanthium

italicum (C0), followed by a pioneer stage with

seedlings of Vitex agnus-castus, Platanus orientalis,

Populus alba and Alnus glutinosa (C1) which require

higher soil moisture for development to a shrubby

pioneer stage (C2). Besides these species a wide

variety of herbs prevail as pioneers.

At higher levels a shrub phase on mixed gravel and

sand develops (BC3, see above) with woody species

(Salix spp., Populus nigra, Platanus orientalis, Pop-

ulus alba, Alnus glutinosa). On larger islands within

the AC and at the elevated floodplain the succession is

leading potentially to an early riparian woodland as the

final stage of a floodplain turnover cycle (BC4).

Platanus and Alnus dominate the tree layer and Rubus

sanctus, Brachypodium sylvaticum are main elements

of the understorey. Floristic differences to Alpine and

Northern Balkan gravel bed rivers are outlined in

Appendix A.

All herb species mentioned above as well as the

dominant floodplain forest species represent different

types of anemochory (wind dispersal). The only

exception is Vitex agnus-castus which is barochorous

and also able to reproduce vegetatively. Dispersal

mode combined with the timing of receding water

levels play an important role for germination and

vegetation development on newly created sand and

gravel bars.

Frequent aggradation of sand supports the spread-

ing of the alien cogongrass Imperata cylindrica. At the

elevated floodplain and at higher locations (‘‘islands’’

within the AC), regular burning and pasturing leads to

a dominance of this species with tussocks of Saccha-

rum ravennae and scattered shrubs of Vitex agnus-

castus and Platanus orientalis as a final degradation

stage (D). Without regular burning or when burning is

stopped, the vegetation would develop into a Platanus

orientalis-Alnus glutinosa woodland.

In the short-lived stagnant erosion pools (A5)

filamentous algae, Chara cf. vulgaris and Nastur-

tion-communities are found. In former active channels

abandoned from the main channel within the flood-

plain (A6), or in wetlands along hillslope streams

entering the floodplain assemblages of Nasturtion,

Glycerio-Sparganion and Phragmition alliances can

develop, followed by Salix triandra and S. alba

leading potentially to an Alnus glutinosa-Populus alba

forest.

Fluvial dynamics as the basis for the high

and specific biodiversity

The widely undisturbed river dynamics in the Vjosa

catchment enables the development of the entire

spectrum of floodplain ecosystems from unvegetated

gravel bars to floodplain forests. They are of outstand-

ing importance and in an excellent conservation status.

All riverine habitats typical for the Vjosa are listed in

Annex 1 of the European Union Habitats Directive

(92/43/EEC, amended document from June 10th,

2013). The riverine habitats 3220, 3250, 3230, 3240,

92D0, 6210 and 92C0 are covering 86% of the total

area of the Pocemi-Kalivaci river corridor. This

underpins the importance of the Vjosa river corridor

at a European scale (Table 3).

The fish fauna is an important indicator for the

ecological integrity of large river systems as a broad

spectrum of habitat conditions are required to fulfil the

habitat needs of different ecological guilds in the

course of their life cycle (Schiemer and Waidbacher

1992). The Balkan rivers are characterized by

123

Landscape Ecol (2020) 35:953–968 963

Europe’s highest concentration of endemic fish

species (Freyhof and Brooks 2011). Shumka et al.

(2018a) list 31 fish species inhabiting the Vjosa river

system including the critically endangered species

Anguilla anguilla (European eel) and endangered

species Aphanius ibericus (Spanish toothcarp) and

Gobio skadarensis (Skadar gudgeon) according to

IUCN criteria. Furthermore, the Vjosa‘s fish fauna is

characterized by several species endemic to the

Balkans e.g. Barbus prespensis (Prespa barbel),

Luciobarbus albanicus (Albanian barbel), Pachy-

chilon pictum (Albanian roach) and Oxynoemacheilus

pindus (Pindus stone loach).

The Vjosa is a large migration corridor for both

anadromous and catadromous species as well as other

saltwater species entering the system. Meulenbroek

(in litt.) documented Anguilla anguilla from 100 mm

up to 510 mm length up to the boarder to Greece.

These findings indicate that Mediterranean rivers are

significant for the conservation of the European eel

stock. The river potentially provides habitat and

spawning sites for anadromous sturgeons (Acipenseri-

dae) such as the critically endangered Acipenser sturio

and Acipenser naccarii, which are found along the

Albanian coast (Freyhof and Brooks 2011). The

assessment of the fish fauna (Meulenbroek et al.

2018) showed distinct differences in the distribution of

species and their ontogenetic stages within the riverine

habitat range (A1–A5) indicating the need for a broad

spectrum of habitat conditions in terms of water depth,

flow velocities and substrate types, that provides the

basis for species and ontogenetic niches of the

characteristic assemblages.

Many taxonomic groups of aquatic and terrestrial

invertebrates are not, or only sparsely treated in the

IUCN Red List, the Bern Convention list or the

Table 3 The characteristics, conservation value and the areal

representation of the four main habitats of the Vjosa floodplain

in the study site. Given are the habitat type (first column), a

short characterization of the habitat type (second column), the

corresponding Natura 2000-habitat type (Council Directive

92/43/EEC of 21 May 1992, version 2013, April 25) (third

column), the corresponding habitat name in the EUNIS

classification 2004/2012 (fourth column), the assessment in

European Red List of Ecosystems EU 28? (Janssen et al.

2016) (fifth column), and an approximation of the area of

occurrence along Vjosa river in the study site (column six).

Abbreviations: EN = endangered, VU = vulnerable, LC = least

concern. The percentage values provided under ‘‘areal repre-

sentation’’ refer to the morphological floodplain of the Pocemi

and Kalivaci area

Habitat type Characteristics FFH-Annex I/Natura 2000a EUNIS habitat

classific. 2004/2012bEU

red

listc

Areal

representation

Gravel/sand bars Highly dynamic,

regularly

flooded

3220 Alpine rivers and the herbaceous

vegetation along their banks

C3.62 Unvegetated

river gravel banks

VU High, 6.8%

Initial vegetation Highly dynamic,

regularly

flooded

3250 Constantly flowing

Mediterranean rivers with Glaucium

flavum

C3.553

Mediterranean

river gravel

habitats

VU High, 20.5%

Mediterranean

riparian scrub

Fairly dynamic,

annually flooded

92D0 Southern riparian galleries and

thickets (Nerio-Tamaricetea,

Securinegion tinctoriae)

F9.31 Oleander,

chaste tree and

tamarisk galleries

LC High, 8.8%

Mediterranean and

Macaronesian

riparian woodland

Pioneer floodplain

forest, regularly

flooded

92C0 Platanus orientalis and

Liquidambar orientalis woods

(Platanion orientalis)

G1.3157 East

Adriatic poplar

galleries

EN Low, 1.8%

aEuropean Commission 2013. Interpretation Manual of European Union Habitats based on Council Directive 92/43/EEC of 21 May

1992 on the conservation of natural habitats and of wild fauna and flora], EUR28 Version, April 25 2013

https://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf

https://eur-lex.europa.eu/legal-content/DE/TXT/PDF/?uri=CELEX:32013L0017&from=DEbEuropean Environment Agency (EEA) 219. EUNIS habitat type hierarchical view. Revised version.[Accessed 2019–08-28] https://

eunis.eea.europa.eu/habitats-code-browser.jspcJanssen J.A.M. et al. 2016. European Red List of Habitats, 2. Terrestrial and freshwater habitats. Publications Office of the European

Union. https://doi.org/10.2779/091,372, Keith et al. 2013

123

964 Landscape Ecol (2020) 35:953–968

Albanian Red List of endangered species. To evaluate

the conservation status of such taxa we have to refer to

their decline in geographic occurrence and population

size in Central Europe over the past decades.

Macroinvertebrates are a main component for the

biological quality assessment in the European Water

Framework Directive (Hering et al. 2010). Our survey,

which gives only a snapshot of the existing diversity at

the catchment scale, yielded 143 species thus far, of

which approx. 50%—according to ‘‘Fauna Europaea’’

(https://fauna-eu.org)—are new to the fauna of Alba-

nia. It includes species endemic to the western Balkans

(e.g. Ephemeroptera: Rhithrogena neretvana, Ecdy-

onurus puma, Ephemerella maculocaudata, and Tri-

choptera: Rhyacophila diakoftensis, Rhyacophila

balcanica, Rhyacophila loxias, Micrasema sericeum,

Thremma anomalum, among others), and vital popu-

lations of pan-European species like the Plecoptera

Marthamea vitripennis and Xanthoperla apicalis, the

Ephemeroptera Neoephemera maxima and Prosopis-

toma pennigerum and the aquatic beetle Potamophilus

acuminatus (Coleoptera: Elmidae). These species

were formerly widely distributed in large, dynamic

rivers across Central and Eastern Europe and are now

on their decline (see Graf et al. 2018, Bauernfeind

2018) and are considered to be endangered at a

European scale. A detailed list with an evaluation of

the conservation status of individual species is pro-

vided in Appendix B).

The significance of the intact fluvial dynamics is

illustrated here with the example of the ground beetle

fauna (Carabidae, see Paill et al. 2018). The species

richness in the Vjosa river corridor is enormous

considering the limited collection time and the small

river section which has been studied so far. 112 species

have been documented. This exceeds the species

richness of carabids in most other near-natural river

systems in Europe (e.g. Plachter 1986). In the

Tagliamento in Northern Italy, for example, 185

carabid species have been found based on an inves-

tigation over the whole river length from headwaters

to the estuary over a period of more than 20 years

(Kahlen 2009). From the 112 species (2,327 speci-

mens) collected on the Vjosa, 70 (1566 specimens)

were exclusively found within the active channel

(AC). The relative abundance of stenotopic riparian

species reached values of 93% to 97% (in terms of

individual numbers) in the regularly flooded levels of

the AC, but only 4% in the higher floodplains. In the

AC the faunistic patterns vary at a small scale between

different habitat types especially in the highly

dynamic initial and early pioneer stages where 36%

of individuals belonged to species almost exclusively

found on gravel substrates (B0–B2) and 57% exclu-

sively on sand (C0–C2). In the older succession stage

(BC3 and D) the proportion of species found exclu-

sively here is low (1–2% of all individuals). Also in

terms of ecological traits (e.g. flight ability, body size)

a clear pattern of habitat preferences is evident: in the

continuously changing early pioneer habitats on sand

(C0–C2), species with high mobility and re-colonisa-

tion capability dominate (e.g. Cicindela monticola

albanica or Bembidion quadricolle) making up 40 to

50% of the abundance. This is linked to the patchy

structure, small size and time-restricted availability of

moist conditions of the sand bar habitats. The large

number of species found and the high percentage of

stenotopic floodplain-species which have become very

rare throughout Europe (e.g. Bembidion quadricolle,

B. scapulare, B. striatum, Stenolophus discophorus,

and Poecilus striatopunctatus) underlines the high

conservation value of the Vjosa. It represents a genetic

pool of international significance (for details see

Appendix C).

Other invertebrate species are also well repre-

sented. Among orthopterans Saga pedo is listed as a

strictly protected species in Appendix II of the Bern

Convention. Sphingonotus coerulans, Acrotylus

insubricus, Xya pfaendleri and Xya variegata, are

listed on the European Red List (see Rabl and Kunz

2018).

Our assessment of the terrestrial vertebrate fauna

also confirms the high ecological value of the project

area. Of the amphibians and reptilians recorded, the

following are listed either in Appendix II of the EU

Habitats Directive- strictly protected fauna species

(Bufotes viridis, Bombina variegata, Testudo her-

manni, Emys orbicularis, Mauremys rivulata, Pseu-

dopus apodus, Podarcis muralis, Podarcis tauricus,

Lacerta trilineata, Lacerta viridis, Natrix tesselata) or

Appendix III—protected fauna species (Bufo bufo,

Rana graeca, Pelophylax kurtmuelleri, Pelophylax

shqipericus, Natrix natrix) of the Bern Convention

(see Frank et al. 2018; Shumka et al. 2018b).

123

Landscape Ecol (2020) 35:953–968 965

Discussion and summary

The Vjosa and its surrounding habitats are of high

conservation value as both the main channel and the

riparian landscape comprise a mosaic of habitat types

with specific turnover cycles along an undisturbed

longitudinal river continuum. A ‘‘natural flood

regime’’ (Poff et al. 1997) associated with a ‘‘natural

sediment regime’’ (Wohl et al. 2015) generate a high

spatio-temporal heterogeneity, a continuous habitat

rejuvenation and biotic successions. The wide range of

habitat types and ecotones in combination with

dynamic water level fluctuations provide the condi-

tions for the specific associations of well adapted

rheophilic and riparian species, and high levels of

alpha, beta and gamma diversity (Ward et al. 1999).

Extensive studies of other large undammed gravel-

bedded rivers in the temperate zone—e.g. the Taglia-

mento in Italy (e.g. van der Nat et al. 2002) or the

Flathead river in Montana, USA (e.g. Stanford et al.

2005)—revealed a similar critical role of fluvial

dynamics for maintaining habitat and biotic biodiver-

sity. In the majority of European countries such

natural characteristics of large, dynamic rivers are no

longer present (see Fig. 1).

The high abundances of a typical and critically

endangered riverine fish community throughout the

whole river course highlight the importance of habitat

diversity and the undisturbed longitudinal river con-

tinuum (Meulenbroek et al. 2018; Schiemer 2000).

The aquatic invertebrate communities harbor viable

populations of highly threatened species that have

largely or completely disappeared from other Euro-

pean rivers. The syntopic occurrence of such pota-

mophilous species underlines the high conservation

value of the Vjosa. The key features of rivers still

colonised by such characteristic guilds in their differ-

ent development stages are high fluvial dynamics

which provide connectivity within a spatio-temporal

habitat mosaic and buffer capacity against physical

disturbances. The same holds true for the riparian

fauna and vegetation. The high numbers and preva-

lences of stenotopic floodplain carabids for example,

are unparalleled, while densities of rare habitat

specialists among the accompanying flora were

entirely unexpected.

Moreover, all species found are classified as typical

elements of the Natura 2000 habitat types 3220 (alpine

fast flowing rivers) and 3230 (alpine rivers, gravel bars

with ligneous vegetation). Thus, the high conservation

value of the Vjosa is evident. With the impending

habitat degradation and fragmentation by dam con-

structions we expect a massive decline in abundances

and the local extinction of several species in the area.

Lessons learned from other European rivers underpin

the negative ecological effects of river-damming (Poff

et al. 2007). Dams homogenize the flow dynamics of

rivers and reduce their geomorphic complexity (Graf

2006).

Decision-makers and stakeholders should be aware

of the profound consequences and major environmen-

tal threats of dam construction on intact rivers

(Tockner et al. 2008). Today, the ecological and

morphological status of highly modified rivers in

many European countries is being improved by costly

restoration measures. Besides environmental issues,

negative socio-economic side-effects should be con-

sidered when deciding on the construction of hydro-

power plants (see Buijse et al. 2005). In the case of the

Vjosa, a major challenge is the high sediment load of

the river that (i) will reduce efficiency of dam

operation while (ii) increasing river bed incision

downstream of the dam and coastal erosion. These

effects will affect the quality-of-life and economic

prospect of the local population (Hauer et al. 2019).

Finally, there are operational and legal concerns

regarding the planned hydropower dams: during the

past 20 years, water body management is developing

standardized operational procedures, which should be

adhered to. In EU countries, for example, river

management must follow the European Water Frame-

work Directive (2000/60/EC), Natura 2000 Directive,

EUBirds and Habitats Directives (92/43/EEC) and EU

Flood Risk Directive (2007/60/EU). These regulations

stipulate that projects have to evaluate short-,

medium-, and long-term impacts on nature and

affected residents and must consider alternative low-

impact concepts. Important water policy instruments

such as the Water Framework Directive of the EU

request a comprehensive catchment-wide planning

process with clearly defined procedural steps. We call

for a platform to be established at the science-policy

interface, where scientists interact with policymakers,

authorities and other stakeholders. Such a platform

should be used to explore scenarios for the sustainable

development of the Vjosa river corridor, acknowledg-

ing the interdependence of the integrity of riverine

ecosystems with economic, social and cultural aspects

123

966 Landscape Ecol (2020) 35:953–968

of human well-being. The present multidisciplinary

baseline studies on the ecological and morphological

status of the Vjosa form a prerequisite for any

assessments of the ecological effects caused by dam

construction. Such studies should be adopted as a

standard for river management in the Balkan area,

where widespread data deficiency currently prevents

the elaboration of appropriate environmental impact

assessments.

Finally, in light of the extraordinary biodiversity

and uniqueness of the Vjosa river-floodplain ecosys-

tem, we call for the Vjosa to be protected by evaluating

different options including the establishment of a

protected area (e.g. national park) to ensure that the

outstanding conservation value is being secured. The

Bern Convention of the European Council has already

opened a case file at the 38th Standing Committee

meeting in 2018 on the Vjosa. The Convention

recommended to the Albanian Government to suspend

all dam projects on the Vjosa river and prepare an

integrated River Basin Management plan, as well as a

strategic environmental impact assessment including

social aspects in collaboration with Greece.

Acknowledgements Open access funding provided by

University of Vienna. We would like to thank our colleagues

who took part in the ‘‘Science week’’ in April 2017, in particular

Klodian Skrame for his help in the bathymetric assessment of

the landscape relief. The field work in Albania received

organizational and financial support from the NGO�sEuronatur, RiverWatch and Eco-Albania. The article benefited

greatly from comments of three anonymous reviewers.

Open Access This article is licensed under a Creative Com-

mons Attribution 4.0 International License, which permits use,

sharing, adaptation, distribution and reproduction in any med-

ium or format, as long as you give appropriate credit to the

original author(s) and the source, provide a link to the Creative

Commons licence, and indicate if changes were made. The

images or other third party material in this article are included in

the article’s Creative Commons licence, unless indicated

otherwise in a credit line to the material. If material is not

included in the article’s Creative Commons licence and your

intended use is not permitted by statutory regulation or exceeds

the permitted use, you will need to obtain permission directly

from the copyright holder. To view a copy of this licence, visit

http://creativecommons.org/licenses/by/4.0/.

References

Bauernfeind E (2018) Mayflies (Ephemeroptera) of the River

Vjosa. Albania Acta ZooBot Austria 155(1):155–162

Buijse AD, Klijn F, Leuven RSEW,Middelkoop H, Schiemer F,

Thorp JH,Wolfert HP (2005) Rehabilitation of large rivers:

references, achievements and integration into river man-

agement. Arch. Hydrobiol. Suppl. 115(Large Rivers

15):715–738

Copp GH, Penaz M (1988) Ecology of fish spawning and

nursery zones in the flood plain, using a new sampling

approach. Hydrobiologia 169(2):209–224

Deslodges JR, Church MA (1989) Wandering gravel bed rivers.

Can Geogr 33:360–364

Drescher A (2018) The Vjosa—the floodplains of an outstand-

ing gravel bed river in southern Albania. Acta ZooBot

Austria 155:85–105

Eco-Masterplan for Balkan rivers (2018) ‘‘Save the Blue Heart

of Europe’’ campaign

Egger G, Randl M, Drescher A (2019) Scientific programme:

baseline survey for an Environmental Impact Assessment

of the River Vjosa in Albania: Vegetation and Riparian

Habitats. Report to Riverwatch

Fauna Europaea: https://fauna-eu.org/cdm_dataportal, assessed

on 17.8.2019

Frank T, Sacdanaku E, Duda M, Bego F (2018) Amphibian and

reptile fauna of the Vjosa river, Albania. Acta ZooBot

Austria 155:323–336

Freyhof J, Brooks E (2011) European red list of freshwater

fishes. Publications Office of the European Union, 61 pp.

DOI:10.2779/85903.

Graf WL (2006) Downstream hydrologic and geomorphic

effects of large dams on American rivers. Geomorphology

79:336–360

Graf W, Grabowski M, Hess M, Heckes U, RabitschW, Vitecek

S (2018) Aquatic invertebrate fauna of the Vjosa in Alba-

nia. Acta ZooBot Austria 155:135–153

Google Earth (2018) Satellite Images Worldwide. Digital

Globe, 2018, http:// www. earth.google.com.

Griffith HI, Krystufek B, Reed JM (2004) Balkan biodiversity:

pattern and process in the European hotspot. Springer,

Netherlands, 358 p

Hauer C, Aigner H, Fuhrmann M, Holzapfel P, Rindler R,

Pessenlehner S, Pucher D, Skrame K, Liedermann M

(2019) Measuring of sediment transport and morphody-

namics at the Vjosa River/Albania. Report to Riverwatch

Hering D, Borja A, Carstensen J, Carvalho L, Elliot M, Feld CK,

Heiskanen A-S, Johnson RK, Moe J, Pont D, Solheim AL,

Van De Bund W (2010) The european water framework

directive at the age of 10: a critical review of the

achievements with recommendations for the future. Sci

Total Environ 408:4007–4029

Hill MO (1979) Twinspan—a Fortran program for arranging

multivariate data in an ordered two-way table by classifi-

cation of individuals and attributes. Cornell Univ, Ithaka,

New York

Janssen JAM, Rodwell JS, Criado MG, Gubbay S, Haynes T,

Nieto A, Sanders N, Lan-ducci F, Loidi J, Ssysmak A,

Tahvanainen T (2016) European red list of habitats. Part 2.

Terrestrial and freshwater habitats. https://doi.org/10.

2779/091372

Kahlen M (2009) Die Kafer der Ufer und Auen des Tagliamento

(II. Beitrag: Erganzende eigene Sammelergebnisse,

Fremddaten, Literatur). Gortania Botanica, Zoologica

31:65–136

123

Landscape Ecol (2020) 35:953–968 967

Keith DA, Rodrıguez JP, Rodrıguez-Clark KM, Nicholson E,

Aapala K, Alonso A, Asmussen M, Bachman S, Basset A,

Barrow EG, Benson JS (2013) Scientific foundations for an

IUCN red list of ecosystems. PLoS ONE 8:1–25

Meulenbroek P, Shumka S, Schiemer F (2018) First recon-

naissance of habitat partitioning and fish diversity in the

alluvial zone of the river Vjosa, Albania. Acta ZooBot

Austria 155:177–186

Nanson GC, Knighton AD (1996) Anabranching rivers: their

cause, character and classification. Earth Surf Proc Land

21:217–239

Paill W, Gunczy J, Hristovski S (2018) The Vjosa-floodplains in

Albania as natural habitat for ground beetles: a hotspot of

rare and stenotopic species (Coleoptera: Carabidae). Acta

ZooBot Austria 155:269–306

Plachter H (1986) Composition of the carabid beetle fauna of

natural riverbanks and of man-made secondary habitats. In:

Den Broer PJ, Thiele H-U, Weber F (eds) Carabid beetles,

their adaptations and dynamics. Gustav Fischer,

pp 509–535

Poff NL, Allan JD, Bain MB, Karr JR, Prestegaard KL, Richter

BD, Sparks RE, Stromberg JC (1997) The natural flow

regime. Bioscience 47:769–784

Poff NL, Olden JD, Merritt DM, Pepin DM (2007) Homoge-

nization of regional river dynamics by dams and global

biodiversity implications. PNAS 104:5732–5737

Rabl D, Kunz G (2018) First insight into the Orthoptera fauna of

the Vjosa river floodplain at Pocem (South Albania). Acta

ZooBot Austria 155:257–267

Schiemer F (2000) Fish as indicators for the assessment of the

ecological integrity of large rivers. Hydrobiologia

422:271–278

Schiemer F, Beqiraj S, GrafW, Miho A (eds) (2018a) The Vjosa

in Albania—a riverine ecosystem of European signifi-

cance. Acta ZooBot Austria 155

Schiemer F, Drescher A, Hauer C, Schwarz U (2018b) The

Vjosa river corridor: a riverine ecosystem of European

significance. Acta ZooBot Austria 155:1–40

Schiemer F,Waidbacher H (1992) Strategies for conservation of

a Danubian Fish Fauna. In: Boon PJ, Calow P, Petts GJ

(eds) River conservation and management. Wiley,

pp 363–382

Shumka S, Meulenbroek P, Schiemer F, Sanda R (2018a) Fishes

of River Vjosa—an annotated checklist. Acta ZooBot

Austria 155:163–176

Shumka S, Bego F, Beqiraj S, Paparisto A, Kashta L, Miho A,

Nika O, Marka J, Shuka L (2018b) The Vjosa catchment—

a natural heritage. Acta ZooBot Austria 155:349–375

Stanford JA, Lorang MS, Hauer FR (2005) The shifting habitat

mosaic of river ecosystems. Verh. Internat Verein Limnol

29:123–136

Tockner K, Bunn SE, Gordon C, Naiman RC, Quinn GP,

Stanford JA (2008) Flood plains: critically threatened

ecosystems. In: NVC Polunin (ed) Aquatic ecosystems:

trends and global prospects, Cambridge University Press,

pp 45–61

Van der Nat D, Schmidt AP, Tockner K, Edwards PJ, Ward JV

(2002) Inundation dynamics in braided floodplains:

Tagliamento River, Northeast Italy. Ecosystems

5:636–647

Ward JV, Tockner K, Schiemer F (1999) Biodiversity of

floodplain river ecosystems: ecotones and connectivity.

Regul Rivers Res Manag 15:125–139

Wohl E, Bledsoe BP, Jacobsen RB, Poff NL, Rathburn SL,

Walters DM, Wilcox AC (2015) The natural sediment

regime in rivers: broadening the foundation for ecosystem

management. Bioscience 65:358–371

Publisher’s Note Springer Nature remains neutral with

regard to jurisdictional claims in published maps and

institutional affiliations.

123

968 Landscape Ecol (2020) 35:953–968